ITEEDU

用JDK动态代理模拟AOP

代理类

package com.iteedu.spring;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

public class SecurityHandler implements InvocationHandler {

	private Object targetObject;

	public Object newProxy(Object targetObject) {
		this.targetObject = targetObject;
		return Proxy.newProxyInstance(
		        targetObject.getClass().getClassLoader(), 
				targetObject.getClass().getInterfaces(), 
				this);

	}

	public Object invoke(Object proxy, Method method, Object[] args)
			throws Throwable {
		checkSecurity();
		Object ret = null;
		try {
			ret = method.invoke(this.targetObject, args);
		}catch(Exception e) {
			e.printStackTrace();
			throw new java.lang.RuntimeException(e);
		}
		return ret;
	}

	private void checkSecurity() {
		System.out.println("----------checkSecurity()---------------");
	}
}

为被代理对象方法前加checkSecurity()功能。

目标类

接口

package com.iteedu.spring;

public interface IUserManager {

	public void addUser(String username, String password);
	public void deleteUser(int id);
	public void modifyUser(int id, String username, String password);
	public String findUserById(int id);
}

实现

package com.iteedu.spring;

public class UserManagerImpl implements IUserManager {

	public void addUser(String username, String password) {
		System.out.println("-------addUser()----------");
	}

	public void deleteUser(int id) {
		System.out.println("-------deleteUser()----------");
	}

	public String findUserById(int id) {
		System.out.println("-------findUserById()----------");
		return null;
	}

	public void modifyUser(int id, String username, String password) {
		System.out.println("-------modifyUser()----------");
	}
}

调用

SecurityHandler handler = new SecurityHandler();
IUserManager userManager = 
    (IUserManager)handler.newProxy(new UserManagerImpl());
userManager.addUser("张三", "123");